There is a strong need for the development and dissemination of effective prevention programs for mental health problems with college students, who are at risk for depression, anxiety, eating disorders, substance use, and many other difficulties (American College Health Association, 2007). Despite the fact that University settings are well suited to deliver such programs, their penetration into this setting, with a few exceptions, is limited. This may be because available effective prevention programs tend to rely on costly, in-person interventions or else target a restricted range of problems. Finding delivery systems that are cost effective and have a high possibility of utilization, such as a web-based course, might solve the problem of accessibility. However, the question of which students/problems to target for prevention still remains. College students tend to be plagued by a variety of mental health concerns. If we prevent one problem at a time, Universities would need to bear the financial and practical burden of multiple prevention programs to address the numerous problems that might develop. An alternative approach is to target core psychological processes that underlie a wide variety of mental health problems. Experiential avoidance (EA), the tendency to avoid unwanted emotions and negative thoughts, contributes to many psychological problems (e.g., Hayes et al., 2004) and Acceptance and Commitment Therapy (ACT;Hayes, Strosahl and Wilson, 1999) has been found to impact these problems through its ability to move experiential avoidance and related processes (Hayes et al., 2006). This project thus seeks to develop a universal web-based ACT prevention course for college students targeting the development and exacerbation of mental health problems. The project will involve the novel adaption of ACT intervention content to an interactive web-based format. A 12-session format will be used with two half-hour course modules for each of the primary treatment components of ACT. Phase I will focus on developing two modules for first year college students-- acceptance of unwanted emotions and defusion from thoughts. Focus groups and interface design testing will be used to better adapt intervention content and program design to college students. The prototype intervention will be evaluated in Phase I in terms of usability and feasibility using think aloud procedures and a subsequent randomized trial. Phase II will expand the intervention to include the final ten ACT course modules (one each in defusion and acceptance of unwanted emotions and feelings, and two each in values clarification;being present;noticing self;and committed action), with targeted content in the committed action module for specific problem areas based on an initial universal screening and treatment tailoring based on participants'reported distress and motivation to change. The Phase II intervention will be evaluated in a randomized trial across various higher education settings. PUBLIC HEALTH RELEVANCE: Mental health problems including depression, anxiety, eating disorders, and substance use disorders are major public health problems in the US that often take root in the college years. The proposed project seeks to prevent the development and exacerbation of mental health problems in college students by targeting a core psychological process that underlies these problems through a web-based educational program. A substantial percentage of the US population is in college at some point in their lives, and successful prevention programs in this setting could have a broad public health impact.